-0.000 279 91 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal -0.000 279 91(10) to 64 bit double precision IEEE 754 binary floating point representation standard (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

What are the steps to convert decimal number
-0.000 279 91(10) to 64 bit double precision IEEE 754 binary floating point representation (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

1. Start with the positive version of the number:

|-0.000 279 91| = 0.000 279 91


2. First, convert to binary (in base 2) the integer part: 0.
Divide the number repeatedly by 2.

Keep track of each remainder.

We stop when we get a quotient that is equal to zero.


  • division = quotient + remainder;
  • 0 ÷ 2 = 0 + 0;

3. Construct the base 2 representation of the integer part of the number.

Take all the remainders starting from the bottom of the list constructed above.

0(10) =


0(2)


4. Convert to binary (base 2) the fractional part: 0.000 279 91.

Multiply it repeatedly by 2.


Keep track of each integer part of the results.


Stop when we get a fractional part that is equal to zero.


  • #) multiplying = integer + fractional part;
  • 1) 0.000 279 91 × 2 = 0 + 0.000 559 82;
  • 2) 0.000 559 82 × 2 = 0 + 0.001 119 64;
  • 3) 0.001 119 64 × 2 = 0 + 0.002 239 28;
  • 4) 0.002 239 28 × 2 = 0 + 0.004 478 56;
  • 5) 0.004 478 56 × 2 = 0 + 0.008 957 12;
  • 6) 0.008 957 12 × 2 = 0 + 0.017 914 24;
  • 7) 0.017 914 24 × 2 = 0 + 0.035 828 48;
  • 8) 0.035 828 48 × 2 = 0 + 0.071 656 96;
  • 9) 0.071 656 96 × 2 = 0 + 0.143 313 92;
  • 10) 0.143 313 92 × 2 = 0 + 0.286 627 84;
  • 11) 0.286 627 84 × 2 = 0 + 0.573 255 68;
  • 12) 0.573 255 68 × 2 = 1 + 0.146 511 36;
  • 13) 0.146 511 36 × 2 = 0 + 0.293 022 72;
  • 14) 0.293 022 72 × 2 = 0 + 0.586 045 44;
  • 15) 0.586 045 44 × 2 = 1 + 0.172 090 88;
  • 16) 0.172 090 88 × 2 = 0 + 0.344 181 76;
  • 17) 0.344 181 76 × 2 = 0 + 0.688 363 52;
  • 18) 0.688 363 52 × 2 = 1 + 0.376 727 04;
  • 19) 0.376 727 04 × 2 = 0 + 0.753 454 08;
  • 20) 0.753 454 08 × 2 = 1 + 0.506 908 16;
  • 21) 0.506 908 16 × 2 = 1 + 0.013 816 32;
  • 22) 0.013 816 32 × 2 = 0 + 0.027 632 64;
  • 23) 0.027 632 64 × 2 = 0 + 0.055 265 28;
  • 24) 0.055 265 28 × 2 = 0 + 0.110 530 56;
  • 25) 0.110 530 56 × 2 = 0 + 0.221 061 12;
  • 26) 0.221 061 12 × 2 = 0 + 0.442 122 24;
  • 27) 0.442 122 24 × 2 = 0 + 0.884 244 48;
  • 28) 0.884 244 48 × 2 = 1 + 0.768 488 96;
  • 29) 0.768 488 96 × 2 = 1 + 0.536 977 92;
  • 30) 0.536 977 92 × 2 = 1 + 0.073 955 84;
  • 31) 0.073 955 84 × 2 = 0 + 0.147 911 68;
  • 32) 0.147 911 68 × 2 = 0 + 0.295 823 36;
  • 33) 0.295 823 36 × 2 = 0 + 0.591 646 72;
  • 34) 0.591 646 72 × 2 = 1 + 0.183 293 44;
  • 35) 0.183 293 44 × 2 = 0 + 0.366 586 88;
  • 36) 0.366 586 88 × 2 = 0 + 0.733 173 76;
  • 37) 0.733 173 76 × 2 = 1 + 0.466 347 52;
  • 38) 0.466 347 52 × 2 = 0 + 0.932 695 04;
  • 39) 0.932 695 04 × 2 = 1 + 0.865 390 08;
  • 40) 0.865 390 08 × 2 = 1 + 0.730 780 16;
  • 41) 0.730 780 16 × 2 = 1 + 0.461 560 32;
  • 42) 0.461 560 32 × 2 = 0 + 0.923 120 64;
  • 43) 0.923 120 64 × 2 = 1 + 0.846 241 28;
  • 44) 0.846 241 28 × 2 = 1 + 0.692 482 56;
  • 45) 0.692 482 56 × 2 = 1 + 0.384 965 12;
  • 46) 0.384 965 12 × 2 = 0 + 0.769 930 24;
  • 47) 0.769 930 24 × 2 = 1 + 0.539 860 48;
  • 48) 0.539 860 48 × 2 = 1 + 0.079 720 96;
  • 49) 0.079 720 96 × 2 = 0 + 0.159 441 92;
  • 50) 0.159 441 92 × 2 = 0 + 0.318 883 84;
  • 51) 0.318 883 84 × 2 = 0 + 0.637 767 68;
  • 52) 0.637 767 68 × 2 = 1 + 0.275 535 36;
  • 53) 0.275 535 36 × 2 = 0 + 0.551 070 72;
  • 54) 0.551 070 72 × 2 = 1 + 0.102 141 44;
  • 55) 0.102 141 44 × 2 = 0 + 0.204 282 88;
  • 56) 0.204 282 88 × 2 = 0 + 0.408 565 76;
  • 57) 0.408 565 76 × 2 = 0 + 0.817 131 52;
  • 58) 0.817 131 52 × 2 = 1 + 0.634 263 04;
  • 59) 0.634 263 04 × 2 = 1 + 0.268 526 08;
  • 60) 0.268 526 08 × 2 = 0 + 0.537 052 16;
  • 61) 0.537 052 16 × 2 = 1 + 0.074 104 32;
  • 62) 0.074 104 32 × 2 = 0 + 0.148 208 64;
  • 63) 0.148 208 64 × 2 = 0 + 0.296 417 28;
  • 64) 0.296 417 28 × 2 = 0 + 0.592 834 56;

We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit) and at least one integer that was different from zero => FULL STOP (Losing precision - the converted number we get in the end will be just a very good approximation of the initial one).


5. Construct the base 2 representation of the fractional part of the number.

Take all the integer parts of the multiplying operations, starting from the top of the constructed list above:


0.000 279 91(10) =


0.0000 0000 0001 0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000(2)

6. Positive number before normalization:

0.000 279 91(10) =


0.0000 0000 0001 0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000(2)

7. Normalize the binary representation of the number.

Shift the decimal mark 12 positions to the right, so that only one non zero digit remains to the left of it:


0.000 279 91(10) =


0.0000 0000 0001 0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000(2) =


0.0000 0000 0001 0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000(2) × 20 =


1.0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000(2) × 2-12


8. Up to this moment, there are the following elements that would feed into the 64 bit double precision IEEE 754 binary floating point representation:

Sign 1 (a negative number)


Exponent (unadjusted): -12


Mantissa (not normalized):
1.0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000


9. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


Exponent (unadjusted) + 2(11-1) - 1 =


-12 + 2(11-1) - 1 =


(-12 + 1 023)(10) =


1 011(10)


10. Convert the adjusted exponent from the decimal (base 10) to 11 bit binary.

Use the same technique of repeatedly dividing by 2:


  • division = quotient + remainder;
  • 1 011 ÷ 2 = 505 + 1;
  • 505 ÷ 2 = 252 + 1;
  • 252 ÷ 2 = 126 + 0;
  • 126 ÷ 2 = 63 + 0;
  • 63 ÷ 2 = 31 + 1;
  • 31 ÷ 2 = 15 + 1;
  • 15 ÷ 2 = 7 + 1;
  • 7 ÷ 2 = 3 + 1;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

11. Construct the base 2 representation of the adjusted exponent.

Take all the remainders starting from the bottom of the list constructed above.


Exponent (adjusted) =


1011(10) =


011 1111 0011(2)


12. Normalize the mantissa.

a) Remove the leading (the leftmost) bit, since it's allways 1, and the decimal point, if the case.


b) Adjust its length to 52 bits, only if necessary (not the case here).


Mantissa (normalized) =


1. 0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000 =


0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000


13. The three elements that make up the number's 64 bit double precision IEEE 754 binary floating point representation:

Sign (1 bit) =
1 (a negative number)


Exponent (11 bits) =
011 1111 0011


Mantissa (52 bits) =
0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000


Decimal number -0.000 279 91 converted to 64 bit double precision IEEE 754 binary floating point representation:

1 - 011 1111 0011 - 0010 0101 1000 0001 1100 0100 1011 1011 1011 0001 0100 0110 1000


How to convert numbers from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point standard

Follow the steps below to convert a base 10 decimal number to 64 bit double precision IEEE 754 binary floating point:

  • 1. If the number to be converted is negative, start with its the positive version.
  • 2. First convert the integer part. Divide repeatedly by 2 the positive representation of the integer number that is to be converted to binary, until we get a quotient that is equal to zero, keeping track of each remainder.
  • 3. Construct the base 2 representation of the positive integer part of the number, by taking all the remainders from the previous operations, starting from the bottom of the list constructed above. Thus, the last remainder of the divisions becomes the first symbol (the leftmost) of the base two number, while the first remainder becomes the last symbol (the rightmost).
  • 4. Then convert the fractional part. Multiply the number repeatedly by 2, until we get a fractional part that is equal to zero, keeping track of each integer part of the results.
  • 5. Construct the base 2 representation of the fractional part of the number, by taking all the integer parts of the multiplying operations, starting from the top of the list constructed above (they should appear in the binary representation, from left to right, in the order they have been calculated).
  • 6. Normalize the binary representation of the number, shifting the decimal mark (the decimal point) "n" positions either to the left, or to the right, so that only one non zero digit remains to the left of the decimal mark.
  • 7. Adjust the exponent in 11 bit excess/bias notation and then convert it from decimal (base 10) to 11 bit binary, by using the same technique of repeatedly dividing by 2, as shown above:
    Exponent (adjusted) = Exponent (unadjusted) + 2(11-1) - 1
  • 8. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal mark, if the case) and adjust its length to 52 bits, either by removing the excess bits from the right (losing precision...) or by adding extra bits set on '0' to the right.
  • 9. Sign (it takes 1 bit) is either 1 for a negative or 0 for a positive number.

Example: convert the negative number -31.640 215 from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point:

  • 1. Start with the positive version of the number:

    |-31.640 215| = 31.640 215

  • 2. First convert the integer part, 31. Divide it repeatedly by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder;
    • 31 ÷ 2 = 15 + 1;
    • 15 ÷ 2 = 7 + 1;
    • 7 ÷ 2 = 3 + 1;
    • 3 ÷ 2 = 1 + 1;
    • 1 ÷ 2 = 0 + 1;
    • We have encountered a quotient that is ZERO => FULL STOP
  • 3. Construct the base 2 representation of the integer part of the number by taking all the remainders of the previous dividing operations, starting from the bottom of the list constructed above:

    31(10) = 1 1111(2)

  • 4. Then, convert the fractional part, 0.640 215. Multiply repeatedly by 2, keeping track of each integer part of the results, until we get a fractional part that is equal to zero:
    • #) multiplying = integer + fractional part;
    • 1) 0.640 215 × 2 = 1 + 0.280 43;
    • 2) 0.280 43 × 2 = 0 + 0.560 86;
    • 3) 0.560 86 × 2 = 1 + 0.121 72;
    • 4) 0.121 72 × 2 = 0 + 0.243 44;
    • 5) 0.243 44 × 2 = 0 + 0.486 88;
    • 6) 0.486 88 × 2 = 0 + 0.973 76;
    • 7) 0.973 76 × 2 = 1 + 0.947 52;
    • 8) 0.947 52 × 2 = 1 + 0.895 04;
    • 9) 0.895 04 × 2 = 1 + 0.790 08;
    • 10) 0.790 08 × 2 = 1 + 0.580 16;
    • 11) 0.580 16 × 2 = 1 + 0.160 32;
    • 12) 0.160 32 × 2 = 0 + 0.320 64;
    • 13) 0.320 64 × 2 = 0 + 0.641 28;
    • 14) 0.641 28 × 2 = 1 + 0.282 56;
    • 15) 0.282 56 × 2 = 0 + 0.565 12;
    • 16) 0.565 12 × 2 = 1 + 0.130 24;
    • 17) 0.130 24 × 2 = 0 + 0.260 48;
    • 18) 0.260 48 × 2 = 0 + 0.520 96;
    • 19) 0.520 96 × 2 = 1 + 0.041 92;
    • 20) 0.041 92 × 2 = 0 + 0.083 84;
    • 21) 0.083 84 × 2 = 0 + 0.167 68;
    • 22) 0.167 68 × 2 = 0 + 0.335 36;
    • 23) 0.335 36 × 2 = 0 + 0.670 72;
    • 24) 0.670 72 × 2 = 1 + 0.341 44;
    • 25) 0.341 44 × 2 = 0 + 0.682 88;
    • 26) 0.682 88 × 2 = 1 + 0.365 76;
    • 27) 0.365 76 × 2 = 0 + 0.731 52;
    • 28) 0.731 52 × 2 = 1 + 0.463 04;
    • 29) 0.463 04 × 2 = 0 + 0.926 08;
    • 30) 0.926 08 × 2 = 1 + 0.852 16;
    • 31) 0.852 16 × 2 = 1 + 0.704 32;
    • 32) 0.704 32 × 2 = 1 + 0.408 64;
    • 33) 0.408 64 × 2 = 0 + 0.817 28;
    • 34) 0.817 28 × 2 = 1 + 0.634 56;
    • 35) 0.634 56 × 2 = 1 + 0.269 12;
    • 36) 0.269 12 × 2 = 0 + 0.538 24;
    • 37) 0.538 24 × 2 = 1 + 0.076 48;
    • 38) 0.076 48 × 2 = 0 + 0.152 96;
    • 39) 0.152 96 × 2 = 0 + 0.305 92;
    • 40) 0.305 92 × 2 = 0 + 0.611 84;
    • 41) 0.611 84 × 2 = 1 + 0.223 68;
    • 42) 0.223 68 × 2 = 0 + 0.447 36;
    • 43) 0.447 36 × 2 = 0 + 0.894 72;
    • 44) 0.894 72 × 2 = 1 + 0.789 44;
    • 45) 0.789 44 × 2 = 1 + 0.578 88;
    • 46) 0.578 88 × 2 = 1 + 0.157 76;
    • 47) 0.157 76 × 2 = 0 + 0.315 52;
    • 48) 0.315 52 × 2 = 0 + 0.631 04;
    • 49) 0.631 04 × 2 = 1 + 0.262 08;
    • 50) 0.262 08 × 2 = 0 + 0.524 16;
    • 51) 0.524 16 × 2 = 1 + 0.048 32;
    • 52) 0.048 32 × 2 = 0 + 0.096 64;
    • 53) 0.096 64 × 2 = 0 + 0.193 28;
    • We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit = 52) and at least one integer part that was different from zero => FULL STOP (losing precision...).
  • 5. Construct the base 2 representation of the fractional part of the number, by taking all the integer parts of the previous multiplying operations, starting from the top of the constructed list above:

    0.640 215(10) = 0.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2)

  • 6. Summarizing - the positive number before normalization:

    31.640 215(10) = 1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2)

  • 7. Normalize the binary representation of the number, shifting the decimal mark 4 positions to the left so that only one non-zero digit stays to the left of the decimal mark:

    31.640 215(10) =
    1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) =
    1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) × 20 =
    1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) × 24

  • 8. Up to this moment, there are the following elements that would feed into the 64 bit double precision IEEE 754 binary floating point representation:

    Sign: 1 (a negative number)

    Exponent (unadjusted): 4

    Mantissa (not-normalized): 1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0

  • 9. Adjust the exponent in 11 bit excess/bias notation and then convert it from decimal (base 10) to 11 bit binary (base 2), by using the same technique of repeatedly dividing it by 2, as shown above:

    Exponent (adjusted) = Exponent (unadjusted) + 2(11-1) - 1 = (4 + 1023)(10) = 1027(10) =
    100 0000 0011(2)

  • 10. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal sign) and adjust its length to 52 bits, by removing the excess bits, from the right (losing precision...):

    Mantissa (not-normalized): 1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0

    Mantissa (normalized): 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100

  • Conclusion:

    Sign (1 bit) = 1 (a negative number)

    Exponent (8 bits) = 100 0000 0011

    Mantissa (52 bits) = 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100

  • Number -31.640 215, converted from decimal system (base 10) to 64 bit double precision IEEE 754 binary floating point =
    1 - 100 0000 0011 - 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100